| Author |
Message |
    
Dave_02_1200
| | Posted on Wednesday, January 08, 2014 - 09:23 am: | 
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The way I understand it, Lakes' friend is not blowing exhaust pressure into the crank.
He is using a one way (out) valve to allow pressure to escape on the downstroke that prevents air from entering on the upstroke.
The resulting crankcase vacuum helps reduce hp loss to internal windage.
Did I get that right? |
Hootowl
| | Posted on Wednesday, January 08, 2014 - 09:49 am: |
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That's what he's doing NOW. Before they put in the PCV valve, the breather was attached to the exhaust. |
S1owner
| | Posted on Wednesday, January 08, 2014 - 02:24 pm: |
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They did not install the vodoo contraption the person was helping a new drag rider out and removed the contraption and put a oneway on.
Not saying exhaust scavaging will not work but is has to be done correctly and the right application in this case it was not correct from a previous installer they removed it and gained back what it had taken away. |
Dave_02_1200
| | Posted on Wednesday, January 08, 2014 - 02:37 pm: |
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OK. Now I understand. A PCV valve sounds like a good idea.
Also, just wondering: If the exhaust has waves that cause alternating high and low pressure inside the exhaust system, would a one way-valve between the crankcase and the exhaust work even better to create a vacuum in the crankcase? |
Lakes
| | Posted on Wednesday, January 08, 2014 - 04:01 pm: |
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i don't think there would be much more to gain from crank breather, as 115mph is a good speed from a carb tubber.
i have an m2 thats got the 2" collector pipe with a restrictive muffler & my speeds where 109mph to 111mph depending on air quality on the day & with n4 cam's & SE 1.7 ratio rockers. now my bike has N6 cams with stock ratio rockers but have never had it to track. i might ride up in Febuary to see how i go, i try to keep fit & keep weight down, as that helps too.
thanks Cyclonecharlie riding dirt turning left great to watch. |
Hootowl
| | Posted on Wednesday, January 08, 2014 - 04:26 pm: |
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The low pressure in the exhaust pulse is not lower than atmosphere, it is simply lower than the pressure in the cylinder being scavenged, so it helps that cylinder breathe. |
Lakes
| | Posted on Thursday, January 09, 2014 - 01:53 am: |
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Hoot i thought this was hooked up to crank case not combustion chamber, though was to lower pressure in crank. |
Kalali
| | Posted on Thursday, January 09, 2014 - 08:06 am: |
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So guys, what's the bottom line here? Is it putting a one way valve before the catch can/filter assembly to allow the goop to travel down and stop the air from getting sucked in? |
Hootowl
| | Posted on Thursday, January 09, 2014 - 09:46 am: |
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"Hoot i thought this was hooked up to crank case not combustion chamber, though was to lower pressure in crank."
I don't recall seeing anyone say that it was attached to the combustion chamber. Not sure how you could do that.
The PCV valve should be attached to the case, or one of the areas of the head where oil can drain back down to the case (valve cover). These are areas where crank case pressure is felt. |
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